Fractures of the Neck of the Femur

Ross K. Leighton, M.D., FRCSC
Halifax, NS

Displaced Femoral Neck Fractures
The most recent randomized controlled trials, Parker et al. in JBJS 2002, 1150-1155, Tidermark et al. JBJS(B) 2003, 380-388, and Rogmark et al., JBJS(B) 2002, 183-188, compared internal fixation for displaced femoral neck fractures versus hemiarthroplasty in elderly patients. The advantages shown with internal fixation include decreased blood loss, decreased operative time, lower transfusion requirements and decreased length of stay, as well as early diminished mortality in debilitated patients. The disadvantages of internal fixation were illustrated by a re-operation rate of 30-46%, more pain with internal fixation than with hemiarthroplasty and decreased early function in the internal fixation group, versus the hemiarthroplasty. In these same groups the loss of fixation or reduction was 9-30%, and this is increased with varus mal-reduction or poor position of fixation. Avascular necrosis rate was reported at 16% and nonunion rate was 33%.

Replacement of the Femoral Head

When to replace the femoral head is, of course, always a difficult question. The main indication appears to be: 1) displaced fractures in patients over the age of 60 (Garden III and IV), 2) pre-existing symptomatic osteoarthritis, 3) inflammatory disease, 4) poor operative risk, i.e., you feel that one operation is the only way to go for these patients, and 5) poor bone quality (in which good fixation is not felt to be attainable).

The main controversial group in displaced fractures, as noted in the fracture fixation section, is in the age range of 60-70 years. This group could be selected for replacement but could be an excellent group for open reduction and internal fixation.

If, indeed, the femoral head is being resected and descarded, what are the choices? They are: 1) an Austin-Moore prosthesis (cementless), 2) Thompson prosthesis, which is with cement, 3) a unipolar (modular large head with the ability to tension the abductors) or bipolar arthroplasty (Figure I), or 4) a total hip replacement.

leighton.fig i


In general, replacement of the femoral head in displaced subcapital hip fractures is best accomplished with a bipolar. The prevalence of postoperative acetabular pain is uncommon for at least the first eight years.

As a historical note, the Austin-Moore arthroplasty has functioned as a good component, and there are many case reports of these actually lasting a long period of time (over 20 years). However, these case reports are not the norm and are the unusual case(s). Its main advantage is that it is cheap and the operation relatively quick to perform. It is of historical interest, but has poor fixation and a marked potential for acetabular erosion. Therefore, it should be limited to non-ambulatory, low demand patients, the typical patient for which it was designed. The bipolar/unipolar arthroplasty is, in most cases, a cemented femoral stem with neck length and acetabular adjustments. This theoretically decreases the stress on the acetabular cartilage. It can be used with a fixed head (unipolar) and is a relatively easy conversion to a total hip arthroplasty if required. It is therefore the ideal implant for most patients with displaced subcapital neck fracture that are community ambulators (Figure II).

leighton.fig ii

Total hip replacement is common in some centres. It has very good predictable long-term results, but a very high risk of early dislocation (see Table I). Also, there is an increased cost, compared to the bipolar arthroplasty. It also has some disadvantages: 1) a greater magnitude of surgery and 2) increased blood loss. Some authors have suggested an increased infection rate in published articles.

Because of this, THR is generally not advisable, except for patients with antecedent symptomatic osteoarthritis, or as a revision for a failed open reduction internal fixation or failed hemiarthroplasty.

What does the recent literature say about hemiarthroplasty versus open reduction internal fixation in displaced femoral neck fractures? Roden et al. in Acta Orthoropedic Scandinavia SCIN 2003 showed a randomized five-year study showing that 34 of 53 of the screw group were re-operated on, compared to only 3 of the 47 bipolar group.

Parker et al. in JBJS 2002, Pantanen et al. and Acta Orthoropedic Scandinavia 2002 reviewed large randomized trials which again demonstrated a significantly higher re-operation in the open reduction internal fixation group, compared to the hemiarthroplasty group, particularly in the Garden III and IV fractures.

The results of bipolar arthroplasty were demonstrated by Haidukerouych et al., Clinical Orthopedics, 2002. They reviewed 212 cemented bipolars with 11.7 year follow-up. Results indicated 96.2% had no or slight pain, 94% overall 10 year survival without difficulties, and 99% survival for acetabular cartilage wear. In a comparison of unipolar versus bipolar arthroplasty, as mentioned above, Corwell et al., Clinical Orthopedics, 1998 and Ong et al. in Journal of Orthopedic Trauma, 2002 showed two randomized studies comparing cemented unipolar (Modular) versus a bipolar. It was only a short-term follow-up of less than three years, but no differences were seen. In other articles they question the use of the more expensive bipolar. This, of course, is geographical and the least costly effective component should be utilized. In Canada, the bipolar is about the same cost as a modular unipolar. In the USA, the modular unipolar is cheaper than the bipolar. This has led to some confusion in the literature.

There is another comparison of the results of an Austin-Moore component, where Jadhaf et al. in the Journal of Postgraduate Medicine, 1996, and Clayer et al., in the American Journal of Orthopedics, 1997, showed generally poor results; 75% of the Moores had mild to severe pain, and had a significant rate of re-operation.

Tidermarte et al. in JBJS, 2003, Rogmark et al., JBJS, 2002 and Rivikvmar et al., Injury, 2000 were all prospective randomized trials, which compared open reduction internal fixation to total hip replacement (cemented) and all three confirmed better results with total hip replacement. Again, it should be noted they did not compare bipolar arthroplasty versus total hip replacement.

The bottom line is that in patients that are over the age of 60 that have displaced fractures involving the femoral neck, it is rare to regret doing a bipolar arthroplasty. However, it is very common to regret doing an open reduction internal fixation in this particular group.

The final recommendations are: 1) In undisplaced, stable fractures, perform an open reduction internal fixation. 2) In displaced fractures replace the head of the femur. 3) Bipolar arthroplasty (cemented stem) is the most reliable and predictable outcome in most patients.

If, indeed, the femoral canal is less than 15 mm in diameter in measurement, and has high quality bone, the use of a fully porous coated component has been advocated. Engh et al. in a series of over 200 patients showed excellent clinical results in uncemented components in this same age group.

This particular fracture and proposed treatment protocol will always be the object of controversy, but we hope the guidelines noted above will help in organizing treatment protocol (See Table II).




References

Best one stop recent Reads on the topic:

1. Clinical Orthop. 2002 Jun. (399) - The whole volume is dedicated to this topic

2. Injury, 2002 Dec; 33 Suppl 3 - This whole supplement is dedicated to the topic

Other Articles

3. Shmidt A.U., Swionkowski M.P. Femoral Neck Fractures, Orthopedic Clin Northe Am. 2002 Jan;33(1) 97-116.Viii.

4. Parker M.J., Dynon Y. Is The Powel Classification Still Valid, Injury,1998 Sept;29(7):521-3.

5. Bray T.J. Femoral Neck Fracture Fixation,Clinical decision Making, Clin. Ortho. 1997 Jan;339,20-31.

6. Obrant K. Orthopedic Treatment of Hip Fractures, Bone 1996 Mar;(3 Suppl);1455-1485.

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